Method and system for providing secure access to private networks

ABSTRACT

Improved approaches for providing secure access to resources maintained on private networks are disclosed. The secure access can be provided through a public network using a standard network browser. Multiple remote users are able to gain restricted and controlled access to at least portions of a private network through a common access point. The solution provided by the invention is not only easily set up and managed, but also able to support many remote users in a cost-effective manner.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/706,181, filed Nov. 3, 2000, and entitled “METHOD AND SYSTEMFOR REQUESTING AND PROVIDING CONTENT FROM SERVER TO CLIENT VIA ANINTERMEDIARY SERVER,” which claims the benefit of U.S. ProvisionalPatent Application No. 60/235,513, filed Sep. 26, 2000, and entitled“ENHANCED BROWSING ENVIRONMENT,” and both of which are herebyincorporated herein by reference.

This application claims priority of U.S. Provisional Patent ApplicationNo. 60/______ (Att. Dkt. No. DANAP005P), filed Nov. 2, 2001, andentitled “METHOD AND SYSTEM FOR PROVIDING REMOTE SECURE ACCESS TOPRIVATE NETWORKS,” which is hereby incorporated herein by reference.

In addition, this application is related to U.S. patent application Ser.No. ______ (Att. Dkt. No. DANAP006), filed concurrently herewith, andentitled “METHOD AND SYSTEM FOR PROVIDING SECURE REMOTE ACCESS TO EMAILRESOURCES ON PRIVATE NETWORKS,” which is hereby incorporated herein byreference. This application is also related to U.S. patent applicationSer. Nos. 09/706,182; 09/706,296; and 09/706,297.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to client-server computing and, moreparticularly, to client-server computing for securely accessingresources over a network.

2. Description of the Related Art

Network browsers (browser applications), such as Netscape Navigator orMicrosoft Explorer, allow users of client machines to request andretrieve resources from remotely located server machines via theInternet. These network browsers can display or render HyperText MarkupLanguage (HTML) documents provided by the remotely located servermachines. Additionally, browsers are able to execute script programsembedded in the HTML documents to provide some local functionality.

Conventionally, network browsers are used to access public networks,such as the Internet. Private networks are normally protected byfirewalls so that network browsers residing on computing machinesoutside the private network are not able to gain access to any resourceson the private network.

While firewalls are effective at protecting against external access toprivate networks, there is often the need for external persons orbusinesses to gain at least limited access to the private networks ofother persons or businesses. For example, a supplier of parts to abusiness customer may be able to better serve their business customer byhaving access to information (e.g., inventory levels or orders)maintained on the private network of the business customer. Oneconventional approach is to allow the supplier's machine to access theprivate network through the firewall via a public network. This providesa “hole” in the firewall that seriously compromises the security of theprivate network. Hence, this conventional approach is normally notpermitted if security is an important concern. Another conventionalapproach is to establish a Virtual Private Network (VPN) with thesupplier's machine. Here, the supplier's machine is also able to accessthe private network through the public network and the firewall, but alldata transmissions are encrypted. Some firewalls support VPNs andprotocols providing the encrypted communications, such as Point-to-PointTunneling Protocol (PPTP), can be used. While VPNs offer remote secureaccess, they are difficult to arrange, configure and manage. Each VPNmust also be provided for each external person or business given accessto the private network. Still further VPNs are costly and each VPNprovides some security exposure to the entire private network.

Thus, there is a need for improved approaches to providing secure remoteaccess to resources maintained on private networks.

SUMMARY OF THE INVENTION

The invention pertains to improved approaches for providing secureaccess to resources maintained on private networks. The secure accesscan be provided through a public network using a standard networkbrowser. Multiple remote users are able to gain restricted andcontrolled access to at least portions of a private network through acommon access point.

The invention can be implemented in numerous ways, including as asystem, method, device, and a computer readable medium. Severalembodiments of the invention are discussed below.

As a method for accessing resources on a private network via anintermediary server, one embodiment of the invention includes at leastthe acts of: receiving a login request from a user for access to theintermediary server; authenticating the user; subsequently receiving aresource request from the user at the intermediary server, the resourcerequest requesting a particular operation with respect to a resourcefrom the private network; obtaining access privileges for the user;determining whether the access privileges for the user permit the userto perform the particular operation at the private network; andpreventing performance of the particular operation at the privatenetwork such that a response to the resource request is not had when ithas been determined that the access privileges for the user do notpermit the user to perform the particular operation at the privatenetwork.

As a method for providing remote access to a private network via anintermediary server, one embodiment of the invention includes at leastthe acts of: receiving a login request from a remote user for access tothe intermediary server; determining whether the remote user ispermitted access to the intermediary server; granting the remote useraccess to the intermediary server when it is determined that the remoteuser is permitted access, the granted access also carries accessprivileges to predetermined portions of the private network;subsequently receiving a resource request from the remote user at theintermediary server, the resource request requesting a particularresource; determining whether the resource request from the remote useris permitted by the access privileges; supplying the particular resourceto the remote user when it is determined that the resource request fromthe user is permitted; and denying the remote user from access to theparticular resource when it is determined that the resource request fromthe user is not permitted.

As an intermediary server system, one embodiment of the inventionincludes at least a web server, a protocol handler and a contenttransformer. The web server receives requests for resources from clientmachines via a network. The protocol handler receives the requests forresources, modifies the requests to be directed to appropriate remoteservers via the private network, and forwards the modified requests forresources to the appropriate remote servers. The content transformerreceives the resources supplied by the appropriate remote servers inresponse to the modified requests and modifies the resources such thatat least certain links contained therein are modified to be directed tothe intermediary server system instead of remote servers.

As a computer readable medium including at least computer program codefor enabling access to resources on a private network via anintermediary server, one embodiment of the invention includes at least:computer code for receiving a resource request from a user at theintermediary server, the resource request requesting a particularoperation with respect to a resource from the private network; computercode for obtaining access privileges for the user; computer code fordetermining whether the access privileges for the user permit the userto perform the particular operation at the private network; and computercode for preventing performance of the particular operation at theprivate network such that a response to the resource request is not hadwhen said computer code for determining determines that the accessprivileges for the user do not permit the user to perform the particularoperation at the private network.

As a computer readable medium including at least computer program codeto facilitate access to a private network via an intermediary server,one embodiment of the invention includes at least: computer program codefor receiving a login request from a user for access to the intermediaryserver; computer program code for determining whether the user ispermitted access to the intermediary server; computer program code forgranting the user access to the intermediary server when the computerprogram code for determining determines that the user is permittedaccess, the granted access also carries access privileges topredetermined portions of the private network; computer program code forsubsequently receiving a resource request from the user at theintermediary server, the resource request requesting a particularresource; computer program code for determining whether the resourcerequest from the user is permitted by the access privileges; computerprogram code for supplying the particular resource to the user when thecomputer program code for determining determines that the resourcerequest from the user is permitted; and computer program code fordenying the user from access to the particular resource when thecomputer program code for determining determines that the resourcerequest from the user is not permitted.

Other aspects and advantages of the invention will become apparent fromthe following detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1A is a block diagram of an information retrieval system accordingto one embodiment of the invention.

FIG. 1B is a block diagram of an information retrieval system accordingto another embodiment of the invention.

FIG. 2A is a block diagram of an intermediary server according to oneembodiment of the invention.

FIG. 2B is a block diagram of a remote access system according to oneembodiment of the invention.

FIG. 3 is a flow diagram of request processing according to oneembodiment of the invention.

FIG. 4 is a flow diagram of authentication processing according to oneembodiment of the invention.

FIG. 5 is a flow diagram of access privilege processing according to oneembodiment of the invention.

FIG. 6 is a flow diagram of operational privilege processing accordingto one embodiment of the invention.

FIG. 7 is a flow diagram of detailed external authentication processingaccording to one embodiment of the invention.

FIGS. 8A and 8B are flow diagrams of file access request processingaccording to one embodiment of the invention.

FIGS. 9A-9C are flow diagrams of web resource request processingaccording to one embodiment of the invention.

FIG. 10 illustrates a diagram of an information retrieval systemaccording to one embodiment of the invention.

FIG. 11 is a flow diagram of URL modification processing according toone embodiment of the invention.

FIG. 12 is a flow diagram of script modification processing according toone embodiment of the invention.

FIGS. 13A and 13B are flow diagrams of script modification processingaccording to another embodiment of the invention.

FIG. 14 is a flow diagram of email request processing according to oneembodiment of the invention.

FIG. 15 is a flow diagram of mail operation processing according to oneembodiment of the invention.

FIG. 16 is a flow diagram of authentication processing according to oneembodiment of the invention.

FIGS. 17A and 17B illustrate an example of a computer system that may beused in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention pertains to improved approaches for providing secureaccess to resources maintained on private networks. The secure accesscan be provided through a public network using a standard networkbrowser. Multiple remote users are able to gain restricted andcontrolled access to at least portions of a private network through acommon access point.

The solution can enable users, such as employees, contractors orpartners, to access resources resident on a private network in a securemanner while being remotely located from a direct connection to theprivate network. The solution provided by the invention is not onlyeasily set up and managed, but also able to support many remote users ina cost-effective manner.

Embodiments of this aspect of the invention are discussed below withreference to FIGS. 1A-17B. However, those skilled in the art willreadily appreciate that the detailed description given herein withrespect to these figures is for explanatory purposes as the inventionextends beyond these limited embodiments.

FIG. 1A is a block diagram of an information retrieval system 100according to one embodiment of the invention. The information retrievalsystem 100 includes a network 102, client machines 104 and 106, anintermediary server 108, remote servers 110 and 112, a private network114, and private servers 116 and 118. The network 102 serves as acommunication medium through which the client machines 104 and 106, theintermediary server 108 and the remote servers 110 and 112 cancommunicate. The network 102 is, for example, a data network which caninclude the Internet, a wide area network, or a local area network. TheInternet refers to a global network of interconnected computers. Theprivate network 114 also serves as a communication medium through whichthe intermediary server 108 and the private servers 116 and 118 cancommunicate. The network 114 is also a data network. Often the privatenetwork 114 is associated with an entity and thus employees operatingcomputing devices on the private network 114 are able to communicatewith the private servers 116 and 118. For example, the private network114 can be referred to as a corporate network or an intranet. However,access to the private network 114 by an outside computing device istypically limited by a firewall (not shown). The intermediary server 108is permitted to communicate with the private network 114 through thefirewall. Here, to the extent a client machine (requestor) is authorizedand permitted, the intermediary server 108 communicates with the privatenetwork 114 on behalf of the client machine (requestor). Theintermediary server 108, in effect, controls the extent to which itallows outside computing devices to access the private network 114.

According to the invention, requests for content residing on the privateservers 116 and 118 can be received from the client machines 104 and106. As used herein, “content” is any information or resource that canbe stored on a server and retrieved by a client. Typically, the contentis embodied as an electronic file and contains text and/or images.Often, the client machines 104 and 106 operate browser applications thatfacilitate requesting and retrieval of content over the network 102 andthe private network 114. In such cases, the content is often returned tothe browser application as a browser-viewable document (e.g., markuplanguage document, webpage, etc.) so that the browser application candisplay the same. The client machines 104 and 106 communicate with anintermediary server 108. Initially, the intermediary server 108determines whether the client machines 104 and 106 seeking the contentare authenticated and permitted such access to the private network 114.Following successful authentication and permission verifications, theintermediary server 108 then, in turn, accesses the private servers 116and 118 residing on the private network 114 on behalf of the clientmachines 104 and 106. Once the intermediary server 108 obtains therequested content from the private servers 116 and 118, the intermediaryserver 108 can directly return the requested content to the clientmachines 104 and 106 or can first modify the requested content and thendeliver it to the client machines 104 and 106.

The modification to the requested content by the intermediary server 108can take a variety of forms. As one example, the intermediary server 108can insert a toolbar into the requested content before delivery to theclient machines 104 and 106. As another example, the intermediary server108 can alter the hyperlinks within the requested content so as to pointto an intermediary server (e.g., the intermediary server 108). Variousother tasks can be performed on the requested content by theintermediary server 108. Additionally, the information retrieval system100 can also support centralized storage at the intermediary server 108of server stored information. The server stored information is oftenreferred to as “cookies,” though cookies are conventionally stored onclient machines.

Although the information retrieval system 100 illustrated in FIG. 1Adepicts only a pair of client machines, a pair of remote servers, asingle intermediary server and a pair of private servers, it should beunderstood that the information retrieval system 100 can support manyclient machines and many server machines. It should also be understoodthat the information retrieval system 100 can also support multipleintermediary servers.

FIG. 1B is a block diagram of an information retrieval system 150according to one embodiment of the invention. The information retrievalsystem 150 is, for example, a more detailed implementation of theinformation retrieval system 100 illustrated in FIG. 1A.

The information retrieval system 150 makes use of the Internet 152 andclient machines 154 and 156 that couple to the Internet 152 throughwired or wireless means. Typically, the client machines 154 and 156operate client-side applications, such as a network browser or a mailapplication. When requestors (users) of the client machines 154 and 156desire to access remote resources, resource requests are sent from theclient machines 154 and 156 through the Internet 152 to an intermediaryserver 158. Typically, the communications between the client machines154 and 156 and the intermediary server 158 are secured by an encryptiontechnique (e.g., Secure Socket Layer (SSL)). The intermediary server 158provides access to an intranet 160. The resources being requested by theclient machines 154 and 156 reside within the intranet 160. Since afirewall typically limits or precludes external access to the intranet160, the intermediary server 158 must be permitted to communicate withthe intranet through the firewall 162. The intranet 160 typicallyincludes various different types of resources that can be accessedelectronically. Typically, these resources are stored on server machinesthat couple to, or form part of, the intranet. As shown in FIG. 1B, theintranet 160 couples to, or includes, an authentication server 164, aweb server 166, a mail server 168, a file server 170 and a log server172. Hence, a given client machine can access any one of the servers164-172 residing within or on the intranet 160 by way of theintermediary server 158. Consequently, a given client machine canrequest and receive resources residing on the web server 166 using anetwork browser application. As another example, the given clientmachine can access the mail resources residing on the mail server 168using a client-side mail application. As still another example, thegiven client machine can access the file server 170 residing within oron the intranet 160 to obtain, store or view electronic files thereon.

The intermediary server 158 is configured to ensure that access to theintranet 160 via the intermediary server 158 remains protected. In thisregard, the requestors that are seeking to access resources or contentresiding on the intranet 160 must be authenticated. The authenticationcan utilize the authentication server 164 residing within or on theintranet 160. In this regard, native authentication techniques utilizedby the intranet 160 can be used in authenticating a requestor at theintermediary server 158. Still further, the intermediary server 158 canbe configured by an administrator such that different requestors (e.g.,users of client machines) can be given different access privileges todifferent resources (e.g., servers) within or on the intranet 160. Thelog server 172 allows the storage of log information pertaining toaccess requests to the intranet 160 at the intermediary server 158. Thelog information can be provided on an application level basis such thatit is more user-discernable.

FIG. 2A is a block diagram of an intermediary server 200 according toone embodiment of the invention. The intermediary server 200 is, forexample, suitable for use as the intermediary server 108 illustrated inFIG. 1.

The intermediary server 200 includes various processing modulestypically implemented by computer program code executed by a processingdevice utilized by the intermediary server. More particularly, theprocessing modules of the intermediary server 200 include a web server202 and a protocol handler 204. The web server 202 couples to clientmachines through a link 206 (via a network) and the protocol handler 204couples to remote servers through a link 208 (via a network). The webserver 202 and the protocol handler 204 also communicate with oneanother as well as with various supporting modules and a data storagedevice 210. The data storage device 210 provides persistent ornon-volatile storage for various data items being maintained by theintermediary server 200. Typically, for each user or requestorassociated with a client machine, the data storage device providesseparate storage.

The processing modules include an authentication manager 212 and anaccess manager 214. The authentication manager 212 managesauthentication processing which serves to determine whether therequestor is who they say they are. The authentication processing can belocal or external to the intermediary server 200. For example, externalauthentication can be provided by an authentication server within aprivate network (e.g., authentication server 164). The access manager214 provides access limitations to the various resources on the privatenetwork. Namely, different requestors can be assigned different levels,types or areas of access privileges. For example, requestor A can accessserver X but not servers Y and Z, and requestor B can access server Yfor read-only and not servers X and Z.

The intermediary server 200 also includes a content transformer 216,which is another processing module that is used to parse requestedcontent received from a remote server and then modify the content inpredetermined ways.

Another processing module that the intermediary server 200 might includeis a cookie manager 218. The cookie manager manages “cookies” such thatthose being received from a remote server are stored to the data storagedevice 210 and those “cookies” previously stored in the data storagedevice 210 are delivered to the remote server at appropriate times. Moregenerally, “cookies” refer to server stored information. Such serverstored information is often set by a remote server and used for session,state or identification purposes.

FIG. 2B is a block diagram of a remote access system 250 according toone embodiment of the invention. The remote access system 250 operatesin a client-server environment to allow users of clients to gain accessto resources at remote servers. In particular, the remote access system250 includes a network browser 254 and a mail client 256. The networkbrowser 254 and the mail client 256 are client applications that operateor run on client machines. Typically, a user or requestor will interactwith these one or more client programs to request resources located onthe remote servers. The network browser 254 and the mail client 256couple to an intermediary server 252 over secure links or connections.The intermediary server 252 also couples to the remote servers througheither secure or unsecure connections or links. The intermediary server252 can support connections to various different servers, such asservers found on private networks. One example of a private network is acorporate network. The servers illustrated in FIG. 2B include a webserver 258, an email server 260, a Windows file server 262, a UNIX fileserver 264, an authentication server 266 and a log server 268.

The intermediary server 252 includes a Secure Socket Layer (SSL) 272that provides encryption handling for the connection or link with theclient applications prior to reaching a front-end protocol handler layer270. The front-end protocol handler layer 270 includes a plurality ofprotocol handlers to handle the different types of incoming protocolsthat may be utilized by the various client applications. As shown inFIG. 2B, the front-end protocol handler layer 270 includes separateprotocol handlers for the protocols of HTTP, IMAP, SMTP, POP, and MAPI.After the appropriate protocol handler has been utilized for an incomingrequest, other functional modules within the intermediary server 252 canthen be utilized. In particular, an access manager 274 can determinewhether the requestor associated with the incoming request is permittedthe type of access being requested. An authentication manager 276 candetermine whether the requestor is able to be authenticated. A contenttransformer 278 can perform transformation of the content of thereceived request or the requested response provided by the remoteserver. A system administration manager 280 allows a systemadministrator to interact with the intermediary server 252 to configureaccess privileges, system configuration and login features.

The intermediary server 252 also includes back-end protocol handlers282. The back-end protocol handlers 282 provide the appropriate protocolfor outgoing and incoming communications with respect to a particularserver. The layer of back-end protocol handlers shown in FIG. 2Bincludes protocol handlers for the protocols of: HTTP, IMAP, SMTP, POP,SMB, NFS, NIS, RADIUS, LDAP, and NT. To the extent that an incomingprotocol to the intermediary server 252 differs from an outgoingprotocol from the intermediary server 252, the content transformer 278can perform the protocol transformations (e.g., translations). Stillfurther, the intermediary server 252 includes a data store 284, a logmanager 286, and a data synchronization manager 288. The data store 284can provide temporary or semi-permanent data storage for the variouscomponents of the intermediary server 252. For example, a local recordfor authentication purposes can be stored for each of the clients orrequestors in the data store 284. In addition, session identifiers, orcookies, for the clients or requestors can also be stored in acentralized fashion in the data store 284. The data synchronizationmanager 288 is a module that enables coupling of one intermediary serverwith another intermediary server to provide fault tolerance. Hence, ifone intermediary server fails, then, through a link 290, the failingintermediary server can couple to an operating intermediary server toprovide some or all of the operations typically associated with anintermediary server. The log manager 286 is provided to enableapplication level logging of various access requests that are madethrough the intermediary server 252. The log formed by the log manager286 is stored in the log server 268.

FIG. 3 is a flow diagram of request processing 300 according to oneembodiment of the invention. The request processing 300 is invokedwhenever a request from a requestor is received by an intermediaryserver, such as the intermediary server 108 illustrated in FIG. 1A, theintermediary server 158 illustrated in FIG. 1B, the intermediary server200 illustrated in FIG. 2A or the intermediary server 252 illustrated inFIG. 2B.

The request processing 300 begins with a decision 302 that determineswhether the received request is a system login request. When thedecision 302 determines that the received request is a system loginrequest, then the request processing 300 attempts to authenticate 304the requestor. The authentication can be performed locally or remotely.Additional details on authentication are provided below. Thereafter, adecision 306 determines whether the requestor has been authenticated.When the decision 306 determines that the requestor cannot beauthenticated, then the login attempt fails and a login page can bereturned 308 to the requestor. The login page facilitates login retry bythe requestor. Following the operation 308, the request processing 300is complete and ends for the case in which the login request failed.

Alternatively, when the decision 306 determines that the requestor isauthenticated, then a session identifier is returned 310 to therequestor. The requestor can refer to a client device or the user of theclient device depending on context. The session identifier is used insubsequent requests to the intermediary server as long as the session isactive. Additionally, an initial access page is returned 312 to therequestor. From the initial access page, the requestor is able to accessvarious resources available on a private network. Following theoperation 312, the request processing 300 is complete and ends for thecase in which the login request was successful.

Besides the processing of login requests, the request processing 300also operates to process all other requests for remote access via theintermediary server. Hence, when the decision 302 determines that thereceived request is not a system login request, then a decision 314determines whether the received request has a valid session identifier.The received request would have a valid session identifier if therequestor has already been authenticated (i.e., logged into theintermediary server) and the session is still valid. Hence, when thedecision 314 determines that the session identifier associated with thereceived request is not valid, then access to the intermediary server isdenied and the login page can be returned 308 to the requestor.Alternatively, when the decision 314 determines that the sessionidentifier is valid, then a decision 316 determines whether the sessionhas timed-out. When the decision 316 determines that the session hastimed-out, then access to the intermediary server is denied and thelogin page can be returned 308 to the requestor. Here, if the requestorhas an invalid session identifier or the session has timed-out, therequestor is forced to login to be authenticated.

On the other hand, when the decision 316 determines that the session hasnot timed-out, then the requestor is permitted to access the privatenetwork via the intermediary server. Thereafter, depending upon the typeof access the requestor is seeking to make, additional processing isperformed to ensure that the requestor gains access to only thoseresources deemed appropriate and intended. In particular, with respectto the request processing 300, access privileges associated with therequestor are obtained 318. The access privileges indicate whichresources the requestor is entitled to access. Next, a decision 320determines whether the particular access type associated with thereceived request is permitted. When the decision 320 determines that theaccess type associated with the received request is not permitted, thenan access denied page is returned 322 to the requestor. Alternatively,when the decision 320 determines that the access type of the receivedrequest is permitted, then the received request is permitted 324 to beprocessed. Here, the processing of the received request enables therequestor to access (e.g., view, retrieve, etc.) the protected resourcesfrom the private network. Following the operations 322 and 324, therequest processing 300 is complete and ends with the received requesthaving been processed only when access is deemed permitted.

FIG. 4 is a flow diagram of authentication processing 400 according toone embodiment of the invention. The authentication processing 400 is,for example, processing associated with the authentication operation 304illustrated in FIG. 3.

The authentication processing 400 begins with a decision 402 thatdetermines whether a local record for the requestor (user) exists. Whenthe decision 402 determines that a local record for the requestor doesexist, then a decision 404 determines whether local or externalauthentication is required. Here, the local record indicates whetherlocal or external authentication should be performed. Besides anindication of whether local or external authentication should beperformed, a local record can also store other useful information, forexample, requestor's (user's) name, time last logged in, account status,etc. When the decision 404 determines that local authentication is to beperformed, a password provided with the login request being processedfor authentication is hashed 406. Hashing is the transformation of astring of characters into another string of characters referred to as a“key” that represents the original string. A hash function can performthe hashing operation. Hashing is often performed in the encryption anddecryption context.

Next, a decision 408 determines whether the hashed password matches astored hash password. When the decision 408 determines that a match ispresent, then the authentication is deemed successful 410.Alternatively, when the decision 408 determines that a match is notpresent, then the authentication is deemed to have failed 412. Further,when the decision 408 determines that there is no match, then an accessfailure can also be logged 414 in a log. In one embodiment, the log canbe provided by a log server. The logging 414 of the access failure canprovide application-level information that facilitates understanding ofthe nature of the access failure that occurred when later viewing thelog. Following the operations 410 and 414, the authentication processing400 is complete and ends with the authentication either succeeding orfailing depending on whether the login request contains the correctpassword.

On the other hand, when the decision 402 determines that a local recordfor the requestor does not exist, then a decision 416 determines whethera local setting is required. A system setting can be used to indicatewhether or not a local record is required. An administrator can use sucha system setting to limit access to only those users having localrecords. When the decision 416 determines that a local setting isrequired, then the authentication is deemed to have failed 412 becausethere is no available local record. Again, the access failure can belogged 414. Alternatively, when the decision 416 determines that a localsetting is not required, or when the decision 404 determines thatexternal authentication is to be performed, then an address and type ofexternal authentication server (EAS) to be used for the authenticationare obtained 418. Different processing is typically performed withdifferent types of external authentication servers. Normally, theseexternal authentication servers are already provided within the privatenetwork for purposes of performing authentications. Typically, there isa system setting that indicates a particular external authenticationserver to be used. Hence, the authentication processing 400 can make useof the native authentication provided by such external authenticationservers. The discussion below pertaining to FIG. 7 provides additionaldetail on different types of external authentications.

Next, a decision 420 determines whether the external authentication hasbeen successful. Here, external authentication is performed dependingupon the particular type of external authentication that has beenindicated. When the decision 420 determines that external authenticationis not successful, then the authentication is deemed to have failed 412.Additionally, the access failure can be logged 414 as previouslydiscussed. On the other hand, when the decision 420 determines that theexternal authentication has been successful, then the authentication isdeemed to be successful 422. Following the operation 422, theauthentication processing 400 is complete and ends with the requestorbeing authenticated.

FIG. 5 is a flow diagram of access privilege processing 500 according toone embodiment of the invention. The access privilege processing 500 is,for example, processing performed by the decision 320 of FIG. 3. Namely,the access privilege processing 500 determines whether the access typebeing requested is permitted by a particular requestor. In effect, theaccess type provides various criteria that can be used to limit accessby requestors. With respect to the embodiment shown in FIG. 5, thecriteria includes source Internet Protocol (IP) address, time-of-day,and operations.

The access privilege processing 500 begins with a decision 502 thatdetermines whether the source IP address associated with the receivedrequest (i.e., the requestor) is authorized. When the decision 502determines that the source IP address associated with the receivedrequest is not authorized, then the access privilege processing 500denies access 504. Here, to reduce risk of unauthorized access, theaccess privilege processing 500 ensures that only those IP addresses ofknown requestors are able to access the private resources.

When the decision 502 determines that the source IP address isauthorized, then a decision 506 determines whether the time at which therequest is being made satisfies a time-of-day access limitation.Typically, this limitation can be configured for all requestors orseparately for each requestor. Here, the intermediary server can beconfigured, if desired, to permit access to private resources onlyduring certain time periods. This, for example, can permit access onlyduring business hours or other limited hours. When the decision 506determines that the time of the received request is not within thetime-of-day permitted, then the access privilege processing 500 deniesaccess 504.

When the time associated with the received request is determined 506 tobe within the time-of-day permitted, a decision 508 determines whetherthe particular operation associated with the received request ispermitted. Here, the incoming request can request various differentoperations to be performed with respect to the private resources. Thesevarious different operations tend to vary with type of application beingprovided. The decision 508 can operate to limit the operations permittedto be used by different requestors. When the decision 508 determinesthat the operation being requested is not permitted, then access isdenied 504. On the other hand, when the decision 508 determines that therequested operation is permitted, then access is permitted 510.Following the operations 504 and 510, the access privilege processing500 is complete and ends.

FIG. 6 is a flow diagram of operational privilege processing 600according to one embodiment of the invention. The operational privilegeprocessing 600 is, for example, performed by the decision 508illustrated in FIG. 5. It should also be noted that the operationalprivilege processing 600 performs the requested operation when suchoperation is determined to be permitted, and thus can be associated withthe operations 320 and 324 of FIG. 3.

The operational privilege processing 600 begins with a decision 602 thatdetermines whether a file browsing operation has been requested. Whenthe decision 602 determines that a file browsing operation has beenrequested, then a decision 604 determines whether file browsing isenabled for the requestor. When the decision 604 determines that filebrowsing is not enabled for the requestor, then access is denied 606 andthus the operational privilege processing 600 ends. Alternatively, whenthe decision 604 determines that file browsing is enabled for therequestor, then a decision 608 determines whether a read or writeoperation is being requested. When the decision 608 determines that awrite operation is requested, a decision 610 determines whether writeaccess is permitted. In one embodiment, the decision 610 determineswhether write access is permitted by the particular requestor making therequest. When the decision 610 determines that write access is notpermitted, then access is denied 606 and thus the operational privilegeprocessing 600 ends. Alternatively, when the decision 610 determinesthat write access is permitted, then write request processing isperformed 612 to carry out the received request. Following the operation612, the operational privilege processing 600 ends with the requestedoperation having been performed.

On the other hand, when the decision 608 determines that a readoperation is being requested, a decision 614 determines whether readaccess is permitted. In one embodiment, the decision 614 determineswhether read access is permitted by the particular requestor making therequest. When the decision 614 determines that read access is notpermitted, then access is denied 606. Alternatively, when the decision614 determines that read access is permitted, then read requestprocessing is performed 616 to carry out the requested operation.Following the operation 616, the operational privilege processing 600 iscomplete and ends with the requested operation having been performed.

On the other hand, when the decision 602 determines that the requestedoperation is not a file browsing operation, a decision 618 determineswhether the requested operation is a web browsing operation. When thedecision 618 determines that the requested operation is a web browsingoperation, a decision 620 determines whether the server associated withthe web browsing operation is accessible to the requestor. When thedecision 620 determines that the server is not accessible to therequestor, then access is denied 606. In one embodiment, theintermediary server can maintain a list of servers that are accessibleby particular requestors. This enables the intermediary server tocontrol the resources that particular requestors are able to browse byserver names. For example, although a private network may includenumerous servers, requestors are able to be individually restricted toaccessing only certain servers. Alternatively, when the decision 620determines that the server associated with the web browsing operation isaccessible to the requestor, then the web browsing request processing isperformed 622. In other words, the requested web browsing operation isperformed 622 because the requestor was entitled to access theparticular server. Following the operation 622, the operationalprivilege processing 600 ends with the requested operation having beenperformed.

On the other hand, when the decision 618 determines that the requestedoperation is not a web browsing operation, then a decision 624determines whether the requested operation is an email operation. Whenthe decision 624 determines that the requested operation is an emailoperation, then a decision 626 determines whether email (electronicmail) is enabled for the requestor. When the decision 626 determinesthat email is not enabled for the requestor, then access is denied 606.Here, the intermediary server is able to control access to emailoperations by particular requestors. Alternatively, when the decision626 determines that email is enabled for the requestor, the emailrequest processing is performed 628. In other words, the requested emailoperation is performed because the requestor had suitable privileges toperform the operation. Following the operation 628, the operationalprivilege processing 600 ends with the requested operation having beenperformed.

Still further, when the decision 624 determines that the requestedoperation is not an email operation, then a decision 630 determineswhether the requested operation is some other operation that ispermitted by the intermediary server. Here, the other operation can beany suitable operation that is facilitated by the intermediary server.In effect, the other operation can represent a generic operation that isavailable on the intermediary server. The other operation can also referto a local operation being performed by the intermediary server withoutaccess to a private network. Examples of local operations can varywidely but can include: adding bookmarks, adding, editing or deletinglocal records, altering file shares, etc. However, the other operationcould also be an operation performed within the private network. Whenthe decision 630 determines that the requested operation is one of theother operations, then a decision 632 determines whether the otheroperation is permitted. When the decision 632 determines that therequested operation is not one of the other operations that arepermitted, then access is denied 606. Alternatively, when the decision632 determines that the other operation is permitted, then the otherrequest processing is performed 634. Following the operation 634, theoperational privilege processing 600 is complete and ends with the othertype of operation having been performed.

On the other hand, when the decision 630 determines that the requestedoperation is not one of the other operations that are permitted (by therequestor), then the operational privilege processing 600 ends withouthaving performed the requested operation. Here, since the requestedoperation was unsupported by the operational privilege processing 600,the requested operation is not processed (i.e., it is blocked) at theintermediary server.

FIG. 7 is a flow diagram of detailed external authentication processing700 according to one embodiment of the invention. The detailed externalauthentication processing 700 is, for example, detailed processingassociated with the decision 420 illustrated in FIG. 4. The detailedexternal authentication processing 700 supports a variety of differenttypes of external authentication systems, including: Network InformationSystem (NIS), Remote Authentication Dial-In User Service (RADIUS),Lightweight Directory Access Protocol (LDAP), and NT domain. Hence, theexternal authentication performed for the intermediary server can useany of a variety of native authentication approaches that a privatenetwork might provide.

The detailed external authentication processing 700 begins with adecision 702 that determines whether the external authentication server(EAS) is NIS. When the external authentication server is NIS, then a NISrecord is read 704. Then, the password provided with the login requestis hashed 706. The hashed password is compared 708 with that providedwithin the NIS record. A decision 710 then determines whether the hashedpasswords match. When the passwords do match, the authenticationsucceeds 712. When the passwords do not match, the authentication fails714.

On the other hand, when the decision 702 determines that the externalauthentication server is not NIS, a decision 716 determines whether theexternal authentication server is RADIUS. When the externalauthentication server is RADIUS, then the username and password providedwith the login request are encrypted 718 using a RADIUS shared secret.The RADIUS shared secret is typically a shared key. Then, the encryptedvalue is sent 720 to the RADIUS server for authentication. A decision722 then determines whether a response from the RADIUS server has beenreceived. The response, when received, indicates 724 success or failureof the authentication.

On the other hand, when the decision 716 determines that the externalauthentication server is not RADIUS, then a decision 726 determineswhether the external authentication server is LDAP. When the decision726 determines that the external authentication server is LDAP, theusername and password provided with the login request are sent 728 tothe LDAP server for authentication. A decision 730 then determineswhether a response from the LDAP server has been received. The response,when received, indicates 732 success or failure of the authentication.

On the other hand, when the decision 726 determines that the externalauthentication server is not LDAP, a decision 734 determines whether theexternal authentication server is NT domain (NT domain server). When thedecision 734 determines that the external authentication server is NTdomain, a random number is obtained 736 from the NT domain server. Thenthe password provided with the login request is hashed 738 with therandom number. Next, the hashed value is sent 740 to the NT domainserver for authentication. A decision 742 then determines whether aresponse from the NT domain server has been received. The responseindicates 744 success or failure of the authentication.

FIGS. 8A and 8B are flow diagrams of file access request processing 800according to one embodiment of the invention. The file access requestprocessing 800 is, for example, the processing performed when a webbrowsing operation has been requested by a requestor. In other words,the file access request processing 800 can, for example, be theprocessing performed by one embodiment of the block 622 of FIG. 6.

The file access request processing 800 begins with a decision 802 thatdetermines whether a server has been discovered. When the decision 802determines that a server has already been discovered, then a decision804 determines whether the file access request seeks to view foldercontents. When the decision 804 determines that the file access requestdoes desire to view folder contents, then the content of the folder isretrieved 806. The retrieved content is then sent 808 to the requestor.

On the other hand, when the decision 804 determines that the file accessrequest does not seek to view folder contents, a decision 810 determineswhether the file access request is requesting a new folder. When thedecision 810 determines that the file access request is seeking torequest a new folder, then the requestor is prompted 812 for a newfolder name. A decision 813 then determines whether a folder name hasbeen received. When the decision 813 determines that a folder name hasnot yet been received, the file access request processing 800 waits forthe folder name. Once the decision 813 determines that the folder namehas been received, the new folder is created 814.

Alternatively, when the decision 810 determines that the file accessrequest does not desire to create a new folder, then a decision 816determines whether the file access request desires to download a file.When the decision 816 determines that the file access request desires todownload a file, then the requested file is downloaded 818 to therequestor. On the other hand, when the decision 816 determines that thefile access request does not desire to download a file, then a decision820 determines whether the file access request desires to upload a file.When the decision 820 determines that the file access request doesdesire to upload a file, then the requested file is uploaded 822 to therequestor. Alternatively, when the decision 820 determines that the fileaccess request does not desire to upload a file, then additional typesof file access requests could be processed, although none are shown inFIG. 8A. Accordingly, following the decision 820 when the file accessrequest does not desire to upload a file (and no additional types offile access requests are supported), then the file access requestprocessing 800 is complete and ends with no file access operation havingbeen performed. Following the blocks 808, 814, 818 and 822, the fileaccess request processing 800 is also complete and ends but does so withthe requested file access having been performed.

Furthermore, when the decision 802 determines that a server has notalready been discovered, then the file access request processing 800performs the processing shown in FIG. 8B. In this case, a list ofavailable servers is initially discovered 824. Then, a decision 826awaits the selection of one of the available servers by the requestor.Once the decision 826 determines that a server selection has beenreceived, then share information for the selected server is retrieved828. In one embodiment, the share information identifies those of thefolders stored on the selected server that are able to be shared withthird parties, such as remote requestors. A decision 830 then determineswhether the information about the server should be made permanent. Whenthe decision 830 determines that the information about the server shouldbe made permanent, then the server information is saved 832. By savingthe server information, the server is made an “available server” suchthat discovery of the availability of the server is not needed withsubsequent logins to the system. On the other hand, when the decision830 determines that the information about the server should not be madepermanent, then the block 832 is bypassed. In any case, following theblock 830 when the server information is not to be made permanent, aswell as following the block 832 when the server information is to bemade permanent, the processing to discover a server is complete and thusthe file access request processing 800 returns to repeat the decision802 and subsequent operations.

FIGS. 9A-9C are flow diagrams of web resource request processing 900according to one embodiment of the invention. The web resource requestprocessing 900 is, for example, performed by an intermediary server,such as the intermediary server 108 illustrated in FIG. 1A or theintermediary server 158 illustrated in FIG. 1B. The web resource requestprocessing 900 is performed to process a web resource request.

Initially, the host name for the appropriate remote server is obtained902. In one embodiment, the host name can be obtained from storage.Here, the storage can, for example, be the data storage device 214illustrated in FIG. 2A. In another embodiment, the host name can beobtained from the URL associated with the web resource request. Afterthe host name for the appropriate remote server is obtained 902, a hostname lookup is performed 904 to obtain an IP address of the appropriateremote server. A connection is then opened 906 (or maintained if alreadyopened) to the remote server. Next, a secure handshake is performed 908between the intermediary server and the remote server as needed. Any“cookies” associated with the obtained host name are then obtained 910.Following the operation 910, the pre-processing of the web resourcerequest at the intermediary server is complete and the request is nowable to be forwarded to the remote server. At this point, the requestfor the web resource with associated “cookies” is sent 912 to the remoteserver.

A decision 914 then determines whether a response has been received.When the decision 914 determines that a response has not yet beenreceived, the web resource request processing 900 awaits such aresponse. Once the decision 914 determines that a response has beenreceived, then a decision 916 determines whether “cookies” are presentin the response. When the decision 916 determines that “cookies” arepresent in the response, then the “cookies” are extracted 918 from theresponse. The extracted “cookies” are then saved 920. Typically, the“cookies” are stored in central storage provided within the intermediaryserver or other storage associated or coupled to the intermediaryserver. Following the operation 920, as well as following the decision916 when it is determined that “cookies” are not present in theresponse, URLs within headers of the response are modified 922.

A decision 924 then determines whether the response is of a type that isto be modified. Here, in general, a response can be of a variety offorms such as HTML, graphics, .pdf, MPEG, or other formats. When thedecision 924 determines that the response is of a type that cannot bemodified (e.g., graphics), then the response can be immediately sent (orforwarded) 926 to the requestor. Then, a decision 928 determines whetherthe response is completed. When the decision 928 determines that theresponse is completed, then the web resource request processing 900returns to repeat the decision 914 and subsequent operations so thatadditional web resource requests can be processed. Alternatively, whenthe decision 928 determines that so far only a portion of the responsehas been sent to the requestor, the web resource request processing 900returns to repeat the decision 914 and subsequent operations or the likeso that subsequent portions of the response can be similarly processed.

On the other hand, when the decision 924 determines that the response isof a type that can be modified (e.g., HTML), then the response isprocessed to modify the response before returning it to the requestor.The processing illustrated in FIG. 9C represents one embodiment ofprocessing that can be performed to modify the response. In particular,a decision 932 determines whether a toolbar is desired. The intermediaryserver can be configured to always, sometimes or never insert thetoolbar. The toolbar can be standardized or customizable by theintermediary server. When the decision 932 determines that a toolbar isdesired, the toolbar HTML is inserted into the response. The toolbarthat is produced by the toolbar HTML can provide controls or contentthat are added to the resulting response so as to facilitate features orfunctionality provided by the intermediary server.

Next, certain URLs within an HTML portion of the response can bemodified 936. In one embodiment, the modifications to the certain URLscan be achieved by modifying the host name portion of URLs withincertain tags of the resulting HTML. In another embodiment, themodifications to the certain URLs can be achieved by adding suffixes tothe certain URLs. The suffixes thus serve to allow the URLs to carryadditional information. Further, certain URLs provided or produced byscripting language portions within the resulting HTML can be modified938. Examples of scripting languages include JavaScript and VBscript. Inone embodiment, a host name portion of the certain URLs provided orproduced by scripting language portions within the resulting HTML aremodified 938. In another embodiment, the certain URLs provided orproduced by scripting language portions are modified 938 to includesuffixes which carry supplemental information. Additional details onmodifying scripting language portions is provided below with referenceto FIGS. 13A and 13B. Thereafter, the modified response is sent 940 tothe requestor.

A decision 942 then determines whether the request has been completed.When the decision 942 determines that the request has been completed,then the web resource request processing 900 is complete and ends. Onthe other hand, when the decision 942 determines that the request is notyet completed, then the web resource request processing 900 returns torepeat the decision 914 and subsequent operations so that remainingportions of the response can be similarly processed upon being received.The web resource request processing 900 can thus operate to process asingle response to a resource request in multiple pieces or blocks ofdata. In such a case, the web resource request processing 900 canprocess a response from a remote server as it arrives so thatresponsiveness to the requestor is not hindered. In this regard, the webresource request processing 900 causes the operations 914-942 to berepeated for each piece or block of data associated with a response.

FIG. 10 illustrates a diagram of an information retrieval system 1000according to one embodiment of the invention. The information retrievalsystem 1000 is generally similar to the information retrieval system 100of FIG. 1A or the information retrieval system 150 of FIG. 1B. Theoperation of the information retrieval system 1000 is discussed belowwith reference to a representative example which illustrates itsoperation according to one embodiment. The information retrieval system1000 includes a client 1002, an intermediary server 1004 with a datastore 1006, and a remote server 1008. It is assumed that the requestprocessing 300 of FIG. 3 has already been performed and that therequestor is permitted to access the requested resource in the mannersought.

The representative example pertains to a secure request which can beinitiated by the user selecting a hyperlink in a displayed webpage inthe content of a web browsing request. The selected hyperlink is assumedto be

-   -   https://secure.danastreet.com/quote/msft:danainfo:host=www.xyz.com        where “https” is the protocol which uses Secure Socket Layer        (SSL), “secure.danastreet.com” is the host name with        “danastreet.com” being a domain and “secure” being a subdomain,        “/quote/msft” being a path to the particular resource being        requested by selection of the hyperlink, “danainfo” is a        keyword, and “www.xyz.com” is the host where the requested        resource resides. Hence, the domain name lookup of the host name        “secure.danastreet.com” is resolved to the IP address of        danastreet.com, which is the intermediary server 1004 for this        example. The request is then sent from the client 1002 to the        intermediary server 1004. The request is, for example, as        follows:

GET: /quote/msft:danainfo:host=www.xyz.com HTTP/1.0 Host:secure.danastreet.com Cookie: DSID = 123xyzzbcOther information can also be included within the request such asadditional cookies, encoding-accepted, etc. The cookie is, in thisexample, a session cookie (session identifier) and is used indetermining whether the client 1002 is authorized for use with theintermediary server 1004.

In the case of a secure request, the host name within the request is notable to directly identify the remote server 1008 where the request iseventually to be delivered. However, the host name for the remote server1008 is obtained from information provided with the request. Moreparticularly, the information (i.e., host variable) is provided as asuffix with the request. In this example, the suffix includes theinformation that the host name of the remote server 1008 is“www.xyz.com”. Once the appropriate host name has been obtained, adomain name lookup on the host name (“www.xyz.com”) is performed. Next,a connection from the intermediary server 1004 and the remote server1008 is opened (or maintained if already opened), and secure handshakingis optionally performed. Any cookies in the data store 1006 associatedwith the host name and the requestor can then be obtained. Next, arequest by the intermediary server 1004 is sent to the remote server1008. The request is, for example, as follows:

GET: /quote/msft HTTP/1.0 Host: www.xyz.com Cookie: xyzUserID = samOther information can also be included within the request. Note that thecookie provided with the original request pertained to the intermediaryserver 1004 and thus is not forwarded with the request to the remoteserver 1008.

The remote server 1008 receives the request and returns a responseheader and some or all of the content of the requested resource. Anexemplary response can have the following format:

HTTP/1.0 200 OK Set-cookie: xyzuserID = Samual, expires = 01-Jul-2002Content-type: text/html Content-length: 2000 Location:https://www.xyz.com/quote/msft <HTML> * * </HTML>Since the response included a “cookie” to be set, the set-cookie commandis removed from the response and then saved in the data store 1006.Next, to the extent they are present, the URLs within the headers aremodified to point to the intermediary server 1004. In this example, thelocation header includes a full path (including host name), namely,https://www.xyz.com/quote/msft, which is thus modified tohttps://secure.danastreet.com/quote/msft:danainfo:host=www.xyz.com,SSL.In this example, not only are the host names modified but variables arealso added to the end (i.e., suffix) of the URL. The variableinformation added is an indication of the host server having therequested resource and an SSL indicator. With this example, the relativeURLs need to be modified to include the variable information(“danainfo:host=www.xyz.com”) at the end of the relative URLs. The hostnames for the relative URLs are properly provided by the browserapplication operating on the client 1002 which causes the current hostname (“secure.danastreet.com”) to be used for such paths. If desired, atoolbar can be inserted into the HTML data to facilitate operations orfunctions supported by the intermediary server 1004. Still further, theURLs within certain tags within the resulting HTML or those produced byscripting languages are modified to point to the intermediary server1004.

For example, if the HTML data included the following hyperlink:

-   -   <a ref=https://www.xyz.com/quote/msft>        then the hyperlink would be modified to the following:

<a ref=https://secure.danastreet.com/quote/msft:danainfo:host=www.xyz.com,SSL>.Also, if the HTML data included the following relative hyperlink:

-   -   <a ref=a.html>        then the hyperlink would be modified to the following:    -   <a ref=a.html:danainfo:host=www.xyz.com,SSL>.        It should be noted that the variable information provided at the        end (i.e., suffix) of the URLs need not be at the actual end.        Here, suffix is used to generally indicate to the right of the        domain name. Indeed, the variable information can be placed in a        variety of different locations in a URL (even to the left of the        domain name). For example, if the original hyperlink itself has        variables such as following the characters “?” or “#”, then the        variable information (“danainfo:host=www.xyz.com”) can, in one        example, be placed before the character “?” or “#” indicating        the original variables. For example, if the HTML data included        the following hyperlink:    -   <a ref=https://www.xyz.com/quote/msft?color=red>        then the hyperlink would be modified to the following:

<a ref=https://secure.danastreet.com/quote/msft:danainfo:host=www.xyz.com?color=red>.Also, if the HTML data included the following relative hyperlink:

-   -   <a ref=a.html?x=1234>        then the hyperlink would be modified to the following:    -   <a ref=a.html:danainfo:host=www.xyz.com?x=1234>.        As still another example, if the HTML data included the        following relative hyperlink:    -   <a ref=a.html, port=1234>        then the hyperlink would be modified to the following:    -   <a ref=a.html:danainfo:host=www.xyz.com, port=1234>.

FIG. 11 is a flow diagram of URL modification processing 1100 accordingto one embodiment of the invention. The URL modification processing 1100is, for example, processing performed by operation 936 of FIG. 9C. TheURL modification processing 1100 can, for example, be performed by thecontent transformer 216 illustrated in FIG. 2A or the contenttransformer 278 illustrated in FIG. 2B.

The URL modification processing 1100 begins by selecting 1102 a targetURL within an HTML portion of the response (e.g., webpage). Typically,one or more target URLs are previously identified by scanning the HTMLdata. Then, a decision 1104 determines whether the target URL is arelative URL. A relative URL inherits the characteristics of its sourceURL. The source URL is the URL associated with the webpage (includingthe resulting HTML) that includes the target URL. When the decision 1104determines that the target URL is a relative URL, then the hostnameand/or port suffix from the source URL are appended 1106 to the targetURL.

Alternatively, when the decision 1104 determines that the target URL isnot a relative URL, then a decision 1108 determines whether the targetURL is associated with a secure request (e.g., HTTPS). When the decision1108 determines that the request for the target URL is a secure request,then a secure indicator (e.g., HTTPS) is added 1110 to the target URL.On the other hand, if the decision 1108 determines that the target URLis not associated with a secure request, the operation 1110 is bypassed.

Following the operation 1110 as well as directly following the decision1108 when the target URL is not associated with a secure request, thenthe host name provided with the target URL is added 1112 elsewhere tothe target URL. For example, the host name provided with the target URLcan be appended to the target URL. Then, the original host name providedwith the target URL is replaced 1114 with a predetermined host name. Inother words, the host name originally provided for the target URL iseffectively rewritten such that the original host name is replaced withthe predetermined host name, but the original host name remains part ofthe target URL. For example, the predetermined host name is the hostname for the appropriate intermediary server.

Next, a decision 1116 determines whether a port number is specified inthe target URL. When the decision 1116 determines that a port number isspecified in the target URL, then a port number suffix is added 1118 tothe target URL. The port number originally specified in the target URLfollowing the host name is removed 1120.

Following the operation 1120, the URL modification processing 1100performs a decision 1122. Additionally, when the decision 1116determines that a port number is not specified in the target URL, noport number processing is needed so the decision 1122 is then performed.The decision 1122 determines whether more target URLs are to beprocessed. As previously noted, these target URLs have been previouslyidentified by scanning the resulting HTML data. When the decision 1122determines that there are more target URLs, then the URL modificationprocessing 1100 returns to repeat the operation 1102 and subsequentoperations so that additional target URLs can be processed.Alternatively, when the decision 1122 determines that there are no moretarget URLs, then the URL modification processing 1100 is complete andends.

FIG. 12 is a flow diagram of a script modification processing 1200according to one embodiment of the invention. The script modificationprocessing 1200 is, for example, performed by operation 938 illustratedin FIG. 9C. In general, the script modification processing 1200 operatesto modify script portions within the resulting HTML.

The script modification processing 1200 initially scans 1202 the HTMLdata (e.g., of the resulting HTML) for a <script> tag. A decision 1204then determines whether a script has been found. When the decision 1204determines that a script has not been found, then a decision 1206determines whether there is more HTML data to be scanned. When thedecision 1206 determines that there is more HTML data to be scanned,then the script modification processing 1200 returns to repeat theoperation 1202 and subsequent operations. Alternatively, when thedecision 1206 determines that there is no more HTML data to be scanned,the script modification processing 1200 is complete and ends.

On the other hand, when the decision 1204 determines that a script hasbeen found, then the script is searched 1208 to locate text strings“http://” or “https://” followed by a host name. A decision 1210 thendetermines whether a URL host name has been found by the searching 1208of the script. When the decision 1210 determines that a URL host namehas not been found, then a decision 1212 determines whether the end ofthe script has been reached. When the decision 1212 determines that theend of the script has not yet been reached, then the script modificationprocessing 1200 returns to repeat the operation 1208 and subsequentoperations. Alternatively, when the decision 1212 determines that theend of the script has been reached, then the script modificationprocessing 1200 returns to repeat the operation 1202 and subsequentoperations so that additional scripts can be found and processed.

On the other hand, when the decision 1210 determines that a URL hostname has been found, then a rewritten host name is produced 1214. Thehost name provided within the script is then replaced 1216 with therewritten host name. Following the operation 1216, the scriptmodification processing 1200 returns to repeat the operation 1208 andsubsequent operations so that additional host names within the scriptcan be similarly processed.

FIGS. 13A and 13B are flow diagrams of a script modification processing1300 according to another embodiment of the invention. The scriptmodification processing 1300 is, for example, performed by operation 938illustrated in FIG. 9C. In general, the script modification processing1300 operates to modify script portions within the resulting HTML.

The script modification processing 1300 initially scans 1301 the HTMLdata (e.g., of the resulting HTML) for a <script> tag. A decision 1302then determines whether a script has been found. When the decision 1302determines that a script has been found, then the script is parsed 1304to determine or locate predetermined properties and functions associatedwith the script. A decision 1306 then determines whether at least oneproperty or function has been found in the script. When the decision1306 determines that at least one property or function has been found,then the script modification processing 1300 continues such that thescript is modified with respect to the properties or functions foundwithin the script so that the script operates as intended even thoughthe intermediary server is interposed between client devices and remoteservers.

In particular, for each property or function found within the script,the processing is as follows. A decision 1308 determines whether aselected property or function found within the script pertains to a readof a cookie property. When the decision 1308 determines that theidentified property or function does pertain to a read of a cookieproperty, then the read of the cookie property is replaced 1310 with aget_cookies function call. Alternatively, when the decision 1308determines that the identified property or function is not a read of acookie property, as well as following the operation 1310, a decision1312 determines whether the identified property or function pertains toa write to a cookie property. When the decision 1312 determines that theidentified property or function does pertain to a write to a cookieproperty, the write to the cookie property is replaced 1314 with a setcookies functions call.

On the other hand, when the decision 1312 determines that the identifiedproperty or function is not associated with a write to a cookieproperty, as well as following the operation 1314, a decision 1316determines whether the identified property or function pertains to awrite to a property that initiates a request. When the decision 1316determines that the identified property or function does pertain to awrite to a property that initiates a request, then the write to theproperty that initiates (causes) a request is replaced 1318 with aset_URL function call. Alternatively, when the decision 1316 determinesthat the identified property or function does not pertain to a write toa property that initiates a request, as well as following the operation1318, a decision 1320 determines whether the identified property orfunction pertains to a read from a property that returns a URL. When thedecision 1320 determines that the identified property or function doespertain to a read from a property that returns a URL, then the read froma property that returns a URL is replaced 1322 with an appropriatestring.

Furthermore, following the decision 1320 when the identified property orfunction does not pertain to a read from a property that returns a URL,as well as following the operation 1322, a decision 1324 determineswhether more properties or functions were found in the script that stillneed to be processed. When additional properties or functions have beenfound and need processing, the script modification processing 1300returns to repeat the decision 1308 and subsequent operations so thatthe additional properties or functions can be similarly processed. Onthe other hand, when the decision 1324 determines that all theproperties or functions that have been found within the script have beenprocessed, then the script modification processing 1300 performs adecision 1326. The decision 1326 is also performed when the decision1302 determines that a script has not been found. The decision 1326determines whether there is more HTML data to be scanned. When thedecision 1326 determines that there is more HTML data to be scanned,then the script modification processing 1300 returns to repeat theoperation 1301 and subsequent operations. Alternatively, when thedecision 1326 determines that there is no more HTML data to be scanned,the script modification processing 1300 is complete and ends.

Representative examples of a get_cookies function, a set cookiesfunction, a set_URL function, and string substitution are providedbelow. These examples are provided to assist understanding and thusshould not be deemed restrictions on any aspect of the invention. Thefollowing examples use JavaScript as the scripting language.

A first example with respect to the get_cookies function and operation1310 is as follows. In this example, the script includes a scriptinstruction

-   -   var c=document.cookie;        which assigns the cookies associated with the document (page) to        the variable c. This script instruction would be replaced with    -   var c=get_cookies (“othercookie=abc”);        which assigns the cookies present on the intermediary server for        the particular domain of the document (page) and the particular        user (e.g., “othercookie=abc”). In addition, the get_cookies        function takes the cookies from the intermediary server as its        argument and adds to it other cookies that are set by the        script.

A second example with respect to the set_cookies function and operation1314 is as follows. In this example, the script includes a scriptinstruction

-   -   document.cookie=“selection=ijk; expires= . . . ”;        which stores the cookies associated with the document (page) in        the browser. This script instruction (statement) is replaced        with    -   document.cookie=set_cookie (“<domain>”, “selection=ijk; expires=        . . . ”;);        which stores the cookies associated with the document (page) in        the browser and also to the intermediary server. The set_cookie        function includes two arguments. The first argument identifies        the domain of the page having the script. The second argument is        the value that was originally being assigned to the        document.cookie property. The set_cookie function combines these        two arguments and sets a cookie called servercookieX with no        expiration, where X represents a distinguishing numeric value.        The browser will cause this cookie to be sent to the        intermediary server. The intermediary server can then        incorporate the cookie into the cookie storage for the user. The        cookie can also be used to expire an existing cookie in storage        for the user. Once the cookie is stored at the intermediary        server, the next page that the intermediary server returns will        cause the servercookieX to expire because it is no longer        needed. Any calls to the set_cookie function will also append        any cookie values provided within the servercookieX.

To further illustrate, consider the following example where a page fromwww.xyz.com has the following script:

document.cookie = “a=b”; var x = document.cookie;.Assume also the www.xyz.com server has previously returned a cookie tothe intermediary server that has a name “id1” with a value “sam”. Thecode above will be transformed into:

document.cookie = set_cookie (“www.xyz.com”, “a=b”); var x = get_cookie(“id1=sam”);.The first line will cause a cookie “servercookie0” to be set that hasthe value “a=b˜domain=www.xyz.com”, hence the whole cookie will be:

-   -   servercookie0=a=b˜domain=www.xyz.com.        Note that the domain part of the servercookie0 is used purely by        the intermediary server so that it knows which domain is setting        the cookie. The second line calls the get_cookies function which        takes its first argument (filled in by the intermediary server        while the script was rewritten) and examines all        servercookie0'cookies at the browser. It concatenates the first        argument together with any servercookieX cookies, and returns        the result:    -   id1=sam; a=b.        Note, this is the same result that would have been returned from        the original page had it not been rewritten.

A third example with respect to the set_URL function and operation 1318is as follows. The set_URL function operates to modify properties thatcause a request. In this example, the script includes a scriptinstruction

-   -   document.location=“http://www.xyz.com/foo.html”;        which directs the browser to a new page. Such a script        instruction can be replaced with

document.location = set_URL( “”,“http://www.xyz.com/foo.html”);.The set_URL function call takes two arguments. The first argument isfilled in by the intermediary server while the script is being rewrittenand contains any parameters that would normally be provided in a suffix(e.g., “danainfo:”) to follow a URL. It is not always needed, as will beexplained below. The second argument is the URL, though it couldactually be a script expression (e.g., function call) that assembles orreturns a URL.

The set_URL function examines the URL being set and rewrites it to be ofa form that will direct the browser to the intermediary server. As notedabove, the modification to URLs can be achieved with various techniques.

If the page is using the host name modification technique, then relativeURLs do not need to be modified since the host name encodes thenecessary information. If the URL is a full URL, then the set_URLfunction has all of the information it needs to convert the URL. Forexample, a suffix (e.g., “:danaInfo:host=xxx”) can be appended to theURL. Thus, if the page that the script appears on is using the host namemodification technique, the first argument is not needed by the set_URLfunction.

Alternatively, if the page upon which the script is present is using theURL suffix technique, then a relative URL that is passed to the set_URLfunction needs to have the same suffix applied to it. In this case, theintermediary server will insert, as the first argument to the set_URLfunction, any arguments that need to be passed in the suffix. Forexample, if the URL of the page is:

-   -   https://secure.danastreet.com/quote/msft:danaInfo:host=www.xyz.com        and a script instruction on the page includes:    -   document.location=“/quote/ibm”;        then the rewritten script instruction would look like:    -   document.location=set_URL(“Host=www.xyz.com”, “/quote/ibm”);        and the returned result from the set_URL function would be:    -   /quote/ibm:danaInfo:host=www.xyz.com        which would result in a request from the browser for:    -   https://secure.danastreet.com/quote/ibm:danaInfo:host=www.xyz.com.        Alternatively, if the script instruction were instead:    -   document.location=“https://www.abc.com/info/msft”;        then the rewritten script instruction would look like:

document.location = set_URL(“Host=www.xyz.com”,“https://www.abc.com/info/msft”); and the returned result from theset_URL function would be:

-   -   https://secure.danastreet.com/info/msft:danaInfo:host=www.abc.com.        Note that, in this case, the first argument to the set_URL        function is not needed because the second argument is a full URL        and contains all of the information necessary to construct the        final URL.

It should be noted that there are many functions or properties that,when written to, can cause the browser to fetch a URL. Some examplesinclude:

window.open(‘url’, ...) form.action = ‘url’; document.location = ‘url’;document.location.replace(‘url’); image.src = ‘url’;.

A fourth example with respect to the string substitution and operation1322 is as follows. The string substitution operates to modifyproperties that return a URL. Here, script instructions that read from aproperty that return a URL are replaced with a constant string. In thisexample, if the script includes var url=document.location; such would bereplaced by:

-   -   var url=“http://www.yahoo.com/foo.html”;.        This operation serves to ensure that any script examining its        environment would not be confused by the fact that the actual        URL of the page is different from what it expects. Note that        there is more than one property that may need to be modified.        Some examples of properties that can be so modified include:

document.location (returns full URL) document.domain (returns just thehostname part of URL).

FIG. 14 is a flow diagram of email request processing 1400 according toone embodiment of the invention. The email request processing 1400 is,for example, suitable for use as the email request processing performedat block 628 of FIG. 6.

The email request processing 1400 initially accepts 1402 a secureconnection with a mail client. Here, the secure connection between themail client and the intermediary server that is being accepted 1402 can,for example, be made secure through use of a Secure Socket Layer (SSL).Next, the requestor is prompted 1404 for authentication. Typically, therequestor is prompted 1404 to enter at least a password that can be usedto authenticate the requestor. A decision 1406 then determines whether apassword has been received. Typically, but not necessarily, the passwordbeing received is encoded in some manner. For example, base-64 encodingis often utilized. When the decision 1406 determines that a password hasbeen received, then the password can be separated 1408 into a mailserver password and an authentication server password. As an example,the received password can include both the mail server password and theauthentication server password separated by a password separator.

Next, the email server attempts to verify 1410 the mail server password.At about the same time, the authentication server password can attemptto be verified 1412 with the authentication server. Next, a decision1414 determines whether both of the verifications of blocks 1410 and1412 have been successful. When the decision 1414 determines that bothof the verifications have been successful, then a hashed version of thepassword is stored 1416. Then, the mail operation processing 1418associated with the email request is performed. On the other hand, whenthe decision 1414 determines that both of the verifications of blocks1410 and 1412 are not successful, then the email request is denied 1420.Following the operations 1418 and 1420, the email request processing1400 is complete and ends.

FIG. 15 is a flow diagram of mail operation processing 1500 according toone embodiment of the invention. The mail operation processing 1500 is,for example, one example of processing that can be performed by theblock 1418 illustrated in FIG. 14.

The mail operation processing 1500 begins with a decision 1502 thatdetermines whether the connection has timed-out or closed. Here, theconnection refers to the secure connection between the mail client andthe intermediary server. When the decision 1502 determines that a secureconnection has timed-out or closed, then email access to the mail serveris denied 1504. Hence, following the block 1504, the mail operationprocessing is complete and ends when the secure connection has timed-outor closed. However, the processing could continue to return a login pageto the requestor to force the requestor to login and be authenticated inorder to gain access to the mail server.

On the other hand, when the decision 1502 determines that an existingconnection has not timed-out or closed, then a decision 1506 determineswhether a command from a mail client has been received. When thedecision 1506 determines that a command from a mail client has not beenreceived, then the mail operation processing 1500 returns to repeat thedecision 1502 and subsequent operations until a command from the mailclient has been received or until the connection has timed-out orotherwise closed.

Once the decision 1506 determines that a command from a mail client hasbeen received, then the command is forwarded 1508 to the mail server.Next, a decision 1510 determines whether a response has been receivedfrom the mail server. When the decision 1510 determines that a responsehas not yet been received from the mail server, then the mail operationprocessing 1500 awaits such a response. Once the decision 1510determines that a response has been received, then certain UniversalResource Locators (URLs) within the response are modified 1512. Forexample, as part of the content transformation, links or URLs are ableto be modified to redirect the links through the intermediary server.Next, the response is sent 1514 to the mail client. Here, the responseis sent to the mail client using the connection that exists between themail client and the intermediary server. Following the block 1514, themail operation processing 1500 returns to repeat the decision 1502 andsubsequent operations so that additional commands can be processed withrespect to the mail server.

FIG. 16 is a flow diagram of authentication processing 1600 according toone embodiment of the invention. The authentication processing 1600represents one embodiment of the block 1412 illustrated in FIG. 14. Inthis embodiment, the intermediary server is able to bypass or avoidactual verification of a password with the authentication server whencertain conditions are met. By doing so, the authentication can, in manycases, be performed very quickly and without the need to burden or annoyrequestors.

The authentication processing 1600 begins with a decision 1602 thatdetermines whether a stored hashed password is available. When a hashedpassword is previously stored (operation 1416 of FIG. 14), the hashedpassword can later be retrieved and used in this regard. Hence, when thedecision 1602 determines that the stored hashed password is available,then the stored hashed password, a time last authorized and a time lastused password are retrieved 1604. Typically, these values are stored inthe data store associated with the intermediary server and are storedvalues that are particular to the requestor.

Next, a decision 1606 determines whether a hash of the received passwordequals the stored hashed password. When the decision 1606 determinesthat the hash of the received password is equal to the stored hashedpassword, then the requestor is, in effect, authenticated, becauseearlier in the session they entered the proper password that was thenauthenticated. Further, a decision 1610 determines whether the timesince the time last authorized is greater than a maximum sessionduration. Here, the variable indicating the duration of time that hasexpired since the time last authorized is compared to the maximumsession duration. Typically, the maximum session duration is set by therequestor or by the system administrator of the intermediary server.

In any case, when the decision 1610 determines that the time since thetime last authorized does not exceed the maximum session duration, thena decision 1612 determines whether the time since the time last usedpassword exceeds a maximum idle time. Here, the variable indicating theduration of time that has expired since the time last used password iscompared to the maximum idle time. When the decision 1612 determinesthat the time since last used the password does not exceed the maximumidle time, then authentication 1614 by the authentication server isdeemed successful without having to interact with the authenticationserver. Hence the authentication with respect to the authorizationserver is able to be bypassed when the hash of the received passwordequals the stored hash password, provided the time since last authorizeddoes not exceed the maximum session duration, and further provided thetime since last used the password does not exceed the maximum idle time.

On the other hand, the password is verified 1608 with the authenticationserver when the special conditions do not exist. For example, when thedecision 1602 determines that the stored hash password is not available,then the verification 1608 with the authentication server is performed.Likewise, when the decision 1606 determines that the hash of thereceived password is not equal to the stored hash password, then theverification 1608 of the password with the authentication server alsoneeds to be performed. Still further, when the decision 1610 determinesthat the time since last authorized exceeds the maximum session durationor when the decision 1612 determines that the time since last used thepassword exceeds the maximum idle time, then the password needs to beverified 1608 with the authentication server.

Following the operations 1608 and 1614, the authentication processing1600 returns to perform other processing, namely, returns to theoperation 1414 illustrated in FIG. 14. Hence, when the verification 1608is able to be bypassed because the above-mentioned special conditionsexist, the authorization processing is greatly simplified and oftenavoids the need to perform complicated authentication processing withrespect to an authentication server or to prompt a requestor forauthentication information.

FIGS. 17A and 17B illustrate an example of a computer system that may beused in accordance with the invention. The computer system can, forexample, correspond to any of the client machines, the intermediaryserver, or the remote or private servers. FIG. 17A shows a computersystem 1721 that includes a display 1723, screen 1725, cabinet 1727,keyboard 1729, and mouse 1731. Mouse 1731 may have one or more buttonsfor interacting with a graphical user interface. The cabinet 1727 housesa removable medium (e.g., CD-ROM) drive 1733, system memory and a harddrive (see FIG. 17B) which may be utilized to store and retrievesoftware programs incorporating computer code that implements theinvention, data for use with the invention, and the like. AlthoughCD-ROM 1735 is shown as an exemplary computer readable storage medium,other computer readable storage media including floppy disk, tape, DVD,flash memory, system memory, and hard drive may be utilized.Additionally, a data signal embodied in a carrier wave (e.g., in anetwork including the Internet) may be the computer readable storagemedium. In one implementation, an operating system for the computersystem 1721 is provided in the system memory, the hard drive, the CD-ROM1735 or other computer readable storage medium and serves to incorporatethe computer code that implements the invention.

FIG. 17B shows a system block diagram of the computer system 1721 usedto perform the processing of an embodiment of the invention. As in FIG.17A, the computer system 1721 includes monitor 1723, keyboard 1729, andmouse 1731. The computer system 1721 further includes subsystems such asa central processor 1751, system memory 1753, fixed storage 1755 (e.g.,hard drive), removable storage 1757 (e.g., compact disk), displayadapter 1759, sound card 1761, speakers 1763, and network interface1765. The central processor 1751 can, for example, execute computerprogram code (e.g., an operating system) to implement the invention. Anoperating system is normally, but necessarily, resident in the systemmemory 1753 during its execution. Other computer systems suitable foruse with the invention may include additional or fewer subsystems. Forexample, another computer system could include more than one processor1751 (i.e., a multi-processor system) or a cache memory.

The system bus architecture of computer system 1721 is represented byarrows 1767. However, these arrows are illustrative of anyinterconnection scheme serving to link the subsystems. For example, alocal bus could be utilized to connect the central processor to thesystem memory and display adapter. The computer system 1721 shown inFIG. 17A is but an example of a computer system suitable for use withthe invention. Other computer architectures having differentconfigurations of subsystems may also be utilized.

Although the above-described embodiments refer to the use of a singleintermediary server within an information retrieval system, it should berecognized that the information retrieval system can also include aplurality of intermediary servers. The various intermediary servers canindividually receive requests from client machines and forward them tothe appropriate servers and return responses back through theintermediary server to the client machine. By having multiple servers,not only can additional processing power be obtained, but loadbalancing, fault tolerance and localization issues can also beaddressed.

The various aspects, features, embodiments or implementations of theinvention described above can be used alone or in various combinations.

The invention is preferably implemented in software, but can beimplemented in hardware or a combination of hardware and software. Theinvention can also be embodied as computer readable code on a computerreadable medium. The computer readable medium is any data storage devicethat can store data which can thereafter be read by a computer system.Examples of the computer readable medium include read-only memory,random-access memory, CD-ROMs, DVDs, magnetic tape, optical data storagedevices, and carrier waves. The computer readable medium can also bedistributed over network-coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion.

The advantages of the invention are numerous. Different embodiments orimplementations may yield one or more of the following advantages. Oneadvantage of the invention is that an intermediary server can beinterposed between remote servers and clients to facilitate secureaccess. Another advantage of the invention is that content requested byclients can be altered to direct subsequent client requests to anintermediary server which, in turn, acquires the requested content forthe clients. Still another advantage of the invention is that anintermediary server can authenticate requestors seeking access toresources on private networks through use of native authenticationprovided by the private network. Yet still another advantage of theinvention is that secure remote access to private networks can easily beprovided for authorized persons at reasonable costs.

The many features and advantages of the present invention are apparentfrom the written description and, thus, it is intended by the appendedclaims to cover all such features and advantages of the invention.Further, since numerous modifications and changes will readily occur tothose skilled in the art, it is not desired to limit the invention tothe exact construction and operation as illustrated and described.Hence, all suitable modifications and equivalents may be resorted to asfalling within the scope of the invention.

1-50. (canceled)
 51. A method comprising: receiving a login request froma user for access to an intermediary server, the intermediary serverstoring an authentication identifier for each of a plurality of users,the authentication identifier identifying an authentication server;accessing, based on the authentication identifier, an authenticationserver, where the authentication server is separate and distinct fromthe intermediary server, to authenticate the user in response to thelogin request; receiving a resource request from the authenticated userat the intermediary server, the resource request requesting a particularoperation with respect to a resource from a private network; andperforming the particular operation at the private network to determinea response to the resource request.